twin engine, toe adjustment?

[jhwh]

Hi, not sure toe is the correct term? but I come from car racing, so figured it might be close enough to grab the attention.

I have a scarab sport with 2x200 mercury efi, the engines has brand new steering columns, all bushings, bolts etc, so all has been reset, in addition the entire steering system is new, new dual hc5345 sylinders, with tie bar kit in between, all in all a very very solid setup Im happy with.

the engines were adjusted to excatly 0 degrees toe in when I rigged it in spring, is this correct? or should I adjust marginally wider up front, meaning toe out so when I'm under power, the marginal slack in everything, will make it go 100% straight?

it might just be optical illusion, but when going full out on my neutral setup, it looks as if I'm getting a very very mild toe in?

regards Anders

all threads are better with videos! I tested it with cleavers for fun, totally useless for acceleration, rough sea etc, but it makes a cool tail, and sounds wicked.

http://www.youtube.com/watch?v=gD5u32eOi-Q

[Toffen]

Hi!

I presume your props are turning outward? If so, the common advise is to toe them in 1/8 inch. Measured at the bullet and tip of prop shaft. The front will be closer than the propshafts.

Cheeers, ToffenG

[jhwh]

yes, regular rotation on SB engine, and counter on other side.

how is "sørlandet" theese days? the oslofjord was 100% flat now with nice sun, but cold, quite a lot of people and nice stands at the "båter i sjøen" messe. and lots of life.

I managed to hit 58.5knots yesterday on GPS, with 150liters of fuel, seeing 60 would be awsome, but doubt the toe inn will help that much?

[Toffen]

Hi!

Nice weather here too :) But I have a flue. Boring stuff. How high is your engines mounted. Do you use some sort of setback? Is your boat 28 feet. If so, I have seen some of them down on the south coast. Balance and propheight is the key I think. And ofcourse the props. I beleive 60 knots are good for such a boat. Especially if its the 28 feet version. Thats a heavy boat and straight V hull.


My Phantom 25 ran 75 mph with twin XR2 (200 hp each) in the hey days. Thats approx. 65 knots. And thats a straight V hull too. Both shorter and lighter. My twin Merc 2,5 EFI SS (280 hp) runs consistently 86 mph. 88 mph on a very good day. Thats 75 - 77 knots.

Cheeers, Toffen

[jhwh]

actual hull length, is 27,5 feet, the setback box is hmm 1,5-1,75 feet perhaps? I can make more exact measurements.

and yes, the boat is darn heavy, we weighed it to aprox 2300kg, without fuel, it can take 400liters. but even with full tank of gas, 10 people, full watertank etc, we managed 55knots and a small note in the policelog, in the no speed limit zone around jomfruland this summer. :)

the heavy, thin, and solid deep V hull makes the handeling in sea very good, wake from other boat is hardly ever noticed no matter the speed, and when longside other boats in say middagsbukta or whever, it hardly moves when a wake comes that sets the other ones rocking.

engines are mounted quite high, the propshaft, flushes with bottom of boat, but the setback, and twin install still gives good cooling without nosecones. I gues they could go even higher, ideally they would be on lifts, but most lifts, provide even more setback, which is not ideal.

engines are quite fresh, BB engines just got 6 new pistons before this season etc.

at what speeds does your phantom begin to become unstable?

btw, Im back to running 4 blade merc props again, the cleavers we horrible for everything, but sound/water column.


quick pics

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[Toffen]

Hi!

The rig sounds great. I also can not add any jacks as the boat gets too stearn heavy. Its only 5,5 feet wide you see. Can you give me some performance numbers? Pitch of propeller, rpms and top speed (thats 70 mph right?). Then we can figure out the slip.

Merc recently released some new versions of the Bravo One prop which could do the trick. Especially one with less tube lenght, as it reduce the transom lift. Another prop to try is Rev4. If you remove the end of the tubelength with 16 mm, you normally gain 1 mph doing so. Try Hydromotive props too. Their Quad X-OB props are fast. I have a pair of labbed Mirage Plus 25 pitch and Hydromotive Quad X-OB with less tube length, you can borrow if you want. My boat will be winterized next weekend. Then it will be derigged and ready for the 350 sci.

Speak soon!

Cheeers, ToffenG